Partial biochemical and physiological mechanisms of Brassica napus mediating resistance to Sclerotinia sclerotiorum

The correlation between mineral elements content,tannin,endogenous oxalic acid content,SOD activity and resistance to Sclerotinia sclerotiorum in Brassica napus was studied.The calcium content in three resistant genotypes M004,ZhongR-888,085,was higher than that in susceptible ones Ganyou5 and 98C40.In the tissue of ZhongR-888,the content was 16.4% higher than that of Ganyou5.The higher content of iron,the more susceptibility of B.napus to S.sclerotioum was.While manganese,zinc,copper contents were not obviously related to resistance to S.sclerotioum.The tannin contents in inoculated varieties were higher than those in non-inoculated varieties.The tannin contents of resistant varieties with or without inoculation were higher than that of susceptible variety 98C40.The malonic aldehyde content did not show obvious relation with resistance.In the tissues of higher resistance variety(M004) oxalic acid content was 22.2% higher than that of susceptible variety(98C40).The PAL activity did not show remarkable differences among different varieties.After inoculation with S.sclerotioum, the SOD activity varied remarkably.The increase of SOD activity in susceptible varieties was greater than that of the resistant varieties.Those with rapid drop in respiration intensity after inoculation had higher resistance.